Program distribution system



NOV. 6, 1934. w R COTTER AL 1,979,313

PROGRAM DISTRIBUTION SYSTEM Filed March 23. 1935 2 Sheets-Sheet l Fig.1.

INVENTORS M/fiam ACafie-r fli /fan f. sand A TTORNEY Nov. 6, 1934.

w. F. COTTER 1-: AL 13 PROGRAM DISTRIBUTION SYSTEM Filed March 23, 1933 2 Sheets-Sheet 2 N kw 3 I N 0- R7 A TT ORNE Y Patented Nov, 6, 1934 UNITED STATES PATENT OFFICE 1,979,313 PROGRAM DISTRIBUTION SYSTEM a corporation of Application March 23, 1933, Serial No. 662,252

14 Claims.

This invention relates to improvements in radio apparatus; and particularly to means for forwarding over the electric light or power wiring of a house or other structure or selected part thereof, radio signals from a receiver to any point chosen to suit the convenience of a listener, for transformation into sounds.

An object of the invention is to provide means whereby the user of a radio receiver may connect a loud speaker to the wiring of a dwelling or other building or apartment, in a room other than that containing the receiver, and still hear an entire program. Hence, with our invention, one can place the receiver in one room and the loud speaker in another room, merely by plugging the conductors of the receiver into a lighting or other outlet socket; without changing the location of the receiver or employing a long conductor running from the receiver to the speaker when the latter is taken to another room where the listener may wish to entertain himself.

The invention is adapted for reception over either an antenna or other signal-carrying wires, such as a telephone circuit or the like, by which radio programs are distributed, in a well-known manner.

It is a further object of the invention to provide means for safely and permanently connecting the receiver to the light or power circuit at any point, to eliminate risk of damage.

Another object of the invention is to confine the radio signals when, after reception and detection, they are impressed upon the wires of a light or power circuit; so that a program cannot be picked up on any of the wires outside of the enclosed space to which the receiver belongs.

The nature and advantages of the invention are more fully set forth in the ensuing description, which shows how the invention is practiced; but we of course reserve the right to make changes in the method and apparatus employed to the extent of alterations in details, but without a departure from the underlying principle of the invention as the latter is defined in the appended claims.

on the drawings:

Fig. 1 is a diagrammatic view showing the connections for the invention;

Fig. 2 shows another arrangement of circuits; and

Fig. 3 indicates a modification of the invention.

The same numerals identify the same parts throughout.

In Fig. 1, the

as shown at 3, is set up in any convenient point in one room and the signals received are to be reproduced in the form of sound effects at the loud speaker 4 in any other room. According to this invention, both the receiver and the loud speaker are connected to the conductors 2; but between the Junction points for the receiver and the loud speaker with the wires 2, and the points where these wires are joined to the mains 1, reactor coils 5 of low impedance are inserted in the leads 2, as broadly claimed in the applicants companion application for power line re- 662,253, filed of even date herewith. These coils are inductively related to each other and they have a magnetic core. They are wound so that their magnetic fields, due to the power or light current, are in opposition. Hence alternating currents which supply the lights or other devices in the circuit of the wires 2 are not obstructed by these coils because the magnetic effects thereof neutralize each other. At the same time any audio frequency oscillations impressed upon the wires 2 are prevented by the coils 5 from passing out to the main leads 1 and are restricted to the space equipped with the circuit 2.

At 6 is shown an antenna to which the receiver 3' is coupled by a transformer 7. This receiver also has its output end coupled by means of a primary 8 in the audio frequency detector circuit thereof to a secondary 9. One end of this secondary is grounded and the other is connected to a movable contact 10. Between the coil 9 and the ground is attached a conductor leading to a relay coil 11, the other teris to be joined by a conductor 13 to the high side of the circuit 2. The opposite or low side is usually grounded at 25 between the reactors 5 and wires 1. At 12 is a fixed contact to be joined by a second conductor 13 to the "low" or grounded side of the circuit 2. The conductors 13 may be connected to a plug 14 having projecting terminals 15 to no 2 engage terminals such as sockets diagrammatically shown at 16, one joined to each of the wires 2. Normally the contact is held by a spring 17 out of engagement with the contact 12. Hence when the terminals and 16 are connected, current will flow from the high side of the circuit 2 to the coil 11 to ground and back to the low side of grounded connection 25. Therefore, the relay will attract the contact 10 and the secondary 9 will be joined to the low side of the circuit 2, so that audio frequency signals can be impressed thereon.

The speaker 4 is connected to a coil 18 coupled to a coil 19 grounded at one end and connected like the coil 9 to a movable terminal 10 at the other. This terminal 10 is adapted to engage a fixed terminal 12 to be united as before through a conductor 13 to one terminal of another plug 14. A similar relay coil 11 is connected to the grounded side of the coil 19 at one end and by way of another wire 13 to a second terminal 20 of the plug 14. The terminals 20 of the plug 14 are adapted to engage terminals 21 which as before may be socket terminals connected to the opposite sides of the circuit 2. Hence when this plug 14 is handled to cause terminals 20 and 21 to engage, current will flow from the high side of the circuit 2 to ground by way of the coil 11. Then the contacts 10 and 12 will close and the speaker will be connected to the same side of the circuit 2 as the receiver 3. At 22 are shown lamp motors or other translating devices supplied with current from the conductors 2.

In operation, whenever signals are picked up by the antenna 6 they are detected in the receiver 3 and impressed upon the low side of the circuit 2. They travel along the low side of the circuit 2 and are forwarded to the speaker 4 where they are reproduced as voice tones or music. The reactors 5 prevent these oscillations from passing out from the wires 2 to the wires 1. Hence the program is confined to the apartment or dwelling having therein the receiver 3, by the leads 2. with the receiver at any place in the dwelling, the listener can connect in the loud speaker at any point in the same or a different room where there is an outlet for a vacuum cleaner or some other appliance. If the wires 2 supply a single room, that room may have several circuits connected in branch relation with the circuit 1; one of these branch circuits being shown at 23. Then the speaker may be connected to the circuit 23 in any room, as well as to the wires of the circuit 2. In other words, the speaker can be connected to any one of several points in the room containing the receiver. And if the conductors 2 have branches, as shown at 23, to all the other rooms of a house or the like, a person may thus use the speaker in any room of a house or apartment separate from the receiver, without moving or changing the location of the latter. He will, in fact, be able to obtain reception at any point under the roof of the house or within the length or breadth of his room or apartment in a structure occupied by several families; and in any event the program will be restricted within prescribed limits. one outside of the particular apartment or dwelling will be able, merely by using a speaker to obtain reception unless a receiver is also employed and connected up in the same way.

In order to work in this way, the speaker and the receiver must be connected to the low side this circuit through the .5 between the wires of the supply circuit and one terminal of the relay coil must be connected to the high side of the supply circuit. If the connections are reversed, however, the contacts 10 and 12 will simply not close and no reception will be afforded. and no damage will result to any of the parts.

As will also be understood the plugs 14 may be of well-known make adapted for insertion into the conductive sockets of an ordinary electric wiring outlet or similar device to be screwed into a lamp socket.

Fig. 2 shows how our invention can be connected to the supply circuits of several houses or buildings or several apartments in one building. Suppose A indicates the main outside conductors and B is a branch line to supply current to three local circuits. Each local circuit may lead to a separate building or to separate apartments in one building. Each of the circuits having the wires 2 will therefore contain reactors B and the points to which the radio receivers and the loud speakers in each house or apartment are to be connected. Then each occupant of the enclosures supplied by the various circuits 2 will be enabled to connect a receiver as before to an outside antenna, place the receiver in one of the rooms, and obtain a program from his own local circuit to the exclusion of the rest by plugging the loud speaker on the leads 2 either in the same room with the receiver or in other rooms.

In Fig. 2 the low side of the circuit B is shown grounded; but separate grounds may of course be used adjacent the reactors 5 on the low sides of the circuits 2. If these circuits are not pro vided with reactors and a single set of reactors is placed in the circuit B between the ground point and the junction of the first of these circuits, then of course radio reception can be obtained by connecting the loud speaker to any one of them.

The invention is also adapted for use not only with antenna A but also with radio programs transmitted over wires, such as the telephone wires which are led into houses, apartments and other buildings. Such a mode of utilizing thr invention is indicated in Fig. 3 where a telephone circuit is indicated at 24 coupled to a radio receiver 3. The detector circuit of this receiver will be coupled as before by means of coils 8 and 9 and the apparatus shown in Fig. 1 to the light and power wires of a house, office building, hotel, etc. Then whenever a radio program is transmitted over the wires 24 it can be picked up by the receiver 3 and forwarded over the light and power lines for the benefit of the individual listeners. The receiver as shown in Fig. 3 can be connected, not merely to one circuit, but to several such circuits, so that the receiver can pick up not only a program coming in over one channel, but also can reproduce a program coming in through additional channels as well. Likewise, several receivers might be employed, coupled to the same circuit, but adjusted to reproduce separate programs, and the different receivers could each be connected to a diflerent local circuit.

While we have described our invention above as being adapted for impressing audio frequency oscillations upon a circuit, it is by no means limited to audio frequency, but may be utilized for higher frequencies. We may also in place of one receiver coupled to the line, employ several receivers in parallel, so as to impress upon the line several groups of high frequency oscillations,

each representing a different program. By employing a speaker having a detector amplifier. made up in the form oi a unit, and connecting such a speaker to the line, any one of these. programs can be reproduced; or, with several such speakers connected at isolated points, for example, in the rooms of diiferent houses or apartments, all the programs can be reproduced at once.

The principal advantage of the reactors is that they make the power or fighting line available at low impedance and do not obstruct the flow of power or lighting current. At most, these reactors introduce only a little extra ohmic resistance. In ordinary lighting circuits the conductors are often enclosed in a metallic sheath, and some capacity between conductors and this sheath always arises. -If the impedance of the source of program current is high and the impedance of the load in the speaker circuit is likewise high, then the potential between conductors and the sheath will be high and the loss through the capacity of the line is great. the other hand, it the impedance of the source of the speaker circuits are both low, then the potential between the conductors and the sheath will be low and loss through the capacity will be greatly reduced. The reactors are designed so as to utilize the latter condition.

We have further found in practice that the use of these reactors tends to prevent flow of power currents from the line to the ground through the program circuits. The reactors therefore serve to prevent disturbing voltages from being set up in the program circuits.

With our invention a radio receiver can be set up in the living. room, for example, downstairs in a house, while any one of the occupants socket or sim- It will be unnecessary for the loud speaker to be joined by a long conductor cord to the receiver; or even to move the loud speaker around from one room to another. because the owner may have several loud speakers in diflerent rooms of his place of abode. if he so desires.

The loud speaker which may be either dynamic or magnetic and the reproducer unit may be provided with means to enable the radio receiver to be switched on or oil; and even to tune the receiver; so that the latter can be controlled fully at the place where the speaker is used.

The points of connection of the receiver and speaker to the leads 2 may be anywhere in these leads relative to the de'.ices 22, so long as said points are to the right of the coils 5.

Having described the invention, what is claimed is:

1. A communication system comprising a power line having connections to a source of supply and a plurality of conductors, circuits between said line and earth to enable signals to be sent and received by way of said line. and an impedance in said conductors between said signal circuits and the power source, said impedance forming a continuous metallic connection for the transmission 01 power current through the remainder oi said power line.

2. The combination of a light or power circuit. having connections to a source of supply, connections between the earth and said circuit, for sending and receiving signals by way of said circuit, and reactors in each side of said circuit nections between the between said last named connections and the source of supply for said circuit, said reactors being wound and mutually positioned to neutralize the magnetic eilects thereof.

3. The combination oi a light or power circuit having connections to tions and the source of supply for said circuit, said reactors being wound and mutually positioned so that the magnetic eiTects thereof are neutralized.

4. The combination of a light or power circuit having connections to a source of supply, conearth and the grounded enable signals to be sent of the latter, and reactors side of the circuit to and received by way in each side of the named connections and the source of supply of said circuit, said reactors being opposition wound upon a common core to neutralize the magnetic e'iTects of same.

5. A communication system comprising a power line having connections to a source of supply, circuits between said line and the earth to enable signals to be sent and received by way of said line, and means in all of the conductors of said line between the circuits and the supply to restrict said signals to a desired portion of said line, said means being adapted to make said line available at low impedance for the transmission and return flow of power current.

6. A communication system comprising a power line having connections to a source of supply, circuits between said line and the earth to enable signals to be sent and received by way of said line, and means in all the conductors of said line between the supply connections therefor and said circuits to confine the signals to a defrequency in the power return circuit to said line. a

7. A communication system comprising a power line having a plurality of conductors, connection for said power line to a source of supply, circuits between the line and earth to enable signals to be sent and received by way of the line, a coil in each of the conductors between said circuits and the supply connections for said line, said coils being inductively related and opposition wound so that the magnetic eilects thereof are neutralized.

8. A communication system comprising a power line having a plurality of conductors, one of which is grounded, connections for said power line to a source of supply, connections between said grounded conductor and the earth to enable signals to be sent and received by way of said line, and a reactor coil in each conductor between said circuits and the supply connections for said line, said coils being inductively related and wound upon a common core so that the magnetic eilects thereof are in opposition.

9. A communication system comprising a power line having a plurality oi conductors, one of which is grounded, connections for said power line to a source of supply. circuits between said line and earth to enable signals to be sentand line. and impedance of said conductors mutually arcircuit between said last.

\ rent thereon and ranged to cancel the respective magnetic nelds and designed to confine the signals to a desired length of said line, and to render said line available at low impedance for the transmission of power current and tending to retain said curprevent the return passage thereof to ground.

10. A communication system comprising a power line having a source of supply, circuits between said line and earth enabling signals to be sent by way of said line, and continuous connection means in said power line for efiecting the non-magnetic transfer of power current along said line, said means oflering a low impedance to currents of power frequency and a higher impedance to currents of signal frequency.

11. A communication system comprising a of supply, circuits line for effecting the non-magnetic transfer of power current along said line, said means oflering a low impedance to currents of power frequency and a higher impedance to currents of signal frequency.

12. A communication system comprising a power line having a source of supply, circuits between said line and earth enabling signals to be sent by way 01! said line, and reactance means forming a continuous metallic path for power currents being inserted in said power line, and connecting the same respective sides on either side of said reactance of said power line.

13. A communication system comprising: a power line having a source 0! supply, circuits between said line and earth enablin signals to be sent by way of said line, and reactance means connected to maintain the metallic continuity of the power line circuit,.whereby a low impedance is presented to power currents flowing around the last named circuit and a higher impedance is presented to signal currents.

14. A communication system comprising a power line having a source of supply, circuits between said line and earth enabling signals to be sent by way of said line, and a reactance means inserted in each side of said power line and continuing said respective sides in an unbroken metallic connection.

F. CO'II'ER. MARION E. BOND. 

